XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1967
overall recovery of iron, copper and phosphorus in the ultra
low grade magnetite ore. Consequently, the feed to the cop-
per recovery process should not be subjected to grinding to
control the overall process cost. As the rougher concentrate
yield of the copper recovery process is minimal, regrinding
can be considered to ensure the copper concentrate’s grade
meets the required standards without significantly increas-
ing energy consumption. Based on these considerations,
the technology route as characterized by performing the
main separation process under rough grinding conditions
and reduced the feed quantity by multistage pre concentra-
tion for this ultra low grade magnetite ore was developed,
as shown in Figure 2.
Iron Recovery
Due to the coarse grained magnetite aggregates embedded
in the ore samples and their strong magnetic properties a
pre concentration test by dry magnetic separation was con-
ducted. The optimal conditions for pre concentration were
determined to be a feed particle size of –3 mm, a drum
speed of 80 r/min, and a magnetic field intensity of 318.4
kA/m. Grind size tests were conducted for the stage grind-
ing and stage magnetic separation process to determine
the grinding fineness of the ore fed into the first stage of
wet magnetic separation, as well as the regrinding fineness
of the rougher concentrate obtained from the same stage.
Magnetic field intensity tests were conducted for three
magnetic separation stages in the stage grinding and stage
magnetic separation process to determine the optimal mag-
netic field intensity,which were 238.8 kA/m, 159.2 kA/m,
and 127.3 kA/m, respectively.
The optimal parameters of the pre concentration, stage
grinding and stage magnetic separation process were deter-
mined by the above mentioned condition tests. The flow-
chart and parameters are shown in Figure 3, and the results
are shown in Table 5. As shown in Figure 3, the grinding
fineness of the ore fed into the first stage of wet magnetic
separation is –0.074 mm, accounting for 40%.
As shown in Table 5, the discarding rate of the dry
magnetic separation is 10.58%, which reduces the grind-
ing cost before subsequent wet magnetic separation. The
stage grinding and stage magnetic separation process itself
can reduce the amount of ore entering re-grinding, thus
lowering costs. It is worth noting, that the yield of rougher
concentrate entering the re-grinding process is only about
15%. The TFe grade of the final iron concentrate obtained
from the iron recovery process is 65.13%, with a TFe recov-
ery of 44.94%.
Phosphorus Recovery
The ore studied in this paper contains phosphorus resources
primarily in the form of independent apatite minerals,
which exhibit good floatability. The recovery of such phos-
phate rock resources with low phosphorus content typically
employs the direct flotation method. Commonly, anionic
surfactant are used in direct flotation during the beneficia-
tion of phosphates. Sodium carbonate (Na2CO3) is mostly
used to maintain a pH of 9.5 in the direct flotation process,
with the addition of requisite water glass in order to depress
the silicate minerals floatation.
To reduce the cost of phosphorus flotation, mines often
utilize a mixed collector, with oxidized paraffin soap as a key
component. However, traditional oxidized paraffin soap
presents problems such as poor selectivity, low solubility,
and sticky foam formation. In some cases, additional heat
may be required during flotation, increasing process com-
plexity and reducing separation index stability. Therefore, it
is important to develop collectors with high selectivity and
strong flotation ability.
Raw ore
Crushing
Pre concentration by dry
magnetic separation
Grinding
Wet magnetic
separation
Copper flotation
Phosphorus
flotation
Tailings
Waste rock
Fe concentrate
Cu concentrate
P concentrate
Figure 2. Technology route
overall recovery of iron, copper and phosphorus in the ultra
low grade magnetite ore. Consequently, the feed to the cop-
per recovery process should not be subjected to grinding to
control the overall process cost. As the rougher concentrate
yield of the copper recovery process is minimal, regrinding
can be considered to ensure the copper concentrate’s grade
meets the required standards without significantly increas-
ing energy consumption. Based on these considerations,
the technology route as characterized by performing the
main separation process under rough grinding conditions
and reduced the feed quantity by multistage pre concentra-
tion for this ultra low grade magnetite ore was developed,
as shown in Figure 2.
Iron Recovery
Due to the coarse grained magnetite aggregates embedded
in the ore samples and their strong magnetic properties a
pre concentration test by dry magnetic separation was con-
ducted. The optimal conditions for pre concentration were
determined to be a feed particle size of –3 mm, a drum
speed of 80 r/min, and a magnetic field intensity of 318.4
kA/m. Grind size tests were conducted for the stage grind-
ing and stage magnetic separation process to determine
the grinding fineness of the ore fed into the first stage of
wet magnetic separation, as well as the regrinding fineness
of the rougher concentrate obtained from the same stage.
Magnetic field intensity tests were conducted for three
magnetic separation stages in the stage grinding and stage
magnetic separation process to determine the optimal mag-
netic field intensity,which were 238.8 kA/m, 159.2 kA/m,
and 127.3 kA/m, respectively.
The optimal parameters of the pre concentration, stage
grinding and stage magnetic separation process were deter-
mined by the above mentioned condition tests. The flow-
chart and parameters are shown in Figure 3, and the results
are shown in Table 5. As shown in Figure 3, the grinding
fineness of the ore fed into the first stage of wet magnetic
separation is –0.074 mm, accounting for 40%.
As shown in Table 5, the discarding rate of the dry
magnetic separation is 10.58%, which reduces the grind-
ing cost before subsequent wet magnetic separation. The
stage grinding and stage magnetic separation process itself
can reduce the amount of ore entering re-grinding, thus
lowering costs. It is worth noting, that the yield of rougher
concentrate entering the re-grinding process is only about
15%. The TFe grade of the final iron concentrate obtained
from the iron recovery process is 65.13%, with a TFe recov-
ery of 44.94%.
Phosphorus Recovery
The ore studied in this paper contains phosphorus resources
primarily in the form of independent apatite minerals,
which exhibit good floatability. The recovery of such phos-
phate rock resources with low phosphorus content typically
employs the direct flotation method. Commonly, anionic
surfactant are used in direct flotation during the beneficia-
tion of phosphates. Sodium carbonate (Na2CO3) is mostly
used to maintain a pH of 9.5 in the direct flotation process,
with the addition of requisite water glass in order to depress
the silicate minerals floatation.
To reduce the cost of phosphorus flotation, mines often
utilize a mixed collector, with oxidized paraffin soap as a key
component. However, traditional oxidized paraffin soap
presents problems such as poor selectivity, low solubility,
and sticky foam formation. In some cases, additional heat
may be required during flotation, increasing process com-
plexity and reducing separation index stability. Therefore, it
is important to develop collectors with high selectivity and
strong flotation ability.
Raw ore
Crushing
Pre concentration by dry
magnetic separation
Grinding
Wet magnetic
separation
Copper flotation
Phosphorus
flotation
Tailings
Waste rock
Fe concentrate
Cu concentrate
P concentrate
Figure 2. Technology route